Magnetic sensor having a physically hard insulation layer over a magnetic bias structure

Abstract

A narrow track-width magnetoresistive sensor by defining a trench formed between first and second hard bias layers and depositing the sensor into the trench. The sensor can include a sensor stack sandwiched between first and second electrically conductive lead layers. First and second electrically insulating side walls are formed at either side of the sensor stack. First and second hard bias layers extend from the sides of the sensor stack, being separated from the sensor stack by the first and second electrically insulating side walls. First and second physically hard insulation layers are provided over each of the hard bias layers.

1. A magnetic head comprising:
 a first electrode; 
 a magnetoresistive sensor having first and second laterally opposed sides formed upon said first electrode; 
 first and second electrically insulating walls formed at said first and second sides of said sensor; 
 first and second magnetic hard bias layers extending laterally outward from said first and second walls; 
 first and second physically hard electrically insulating layers formed over said first and second hard bias layers, the first and second physically hard electrically insulating layers being constructed of a material that is resistant to removal by chemical mechanical polishing, and being formed such that no portion of the first and second physically hard electrically insulating layers extend over the sensor; and 
 a second electrode formed over said sensor and said physically hard electrically insulating layers. 
 
     
     
       2. A magnetic head as in  claim 1 , wherein said physically hard electrically insulating layers comprise alumina (Al 2 O 3 ). 
     
     
       3. A magnetic head as in  claim 1  wherein the first and second electrically insulating walls comprise SiO 2 . 
     
     
       4. A magnetic data memory system, comprising:
 magnetic disk; 
 a motor connected with said disk rotating said disk; 
 a slider; 
 an actuator connected with said slider to position said slider adjacent said disk; 
 a magnetic sensor connected with said slider, said sensor comprising:
 a first electrode; 
 a magnetoresistive sensor having first and second laterally opposed sides formed upon said first electrode; 
 first and second electrically insulating walls formed at said first and second sides of said sensor; 
 first and magnetic hard bias layers extending laterally outward from said first and second walls; 
 first and second physically hard electrically insulating layers formed over said first and second hard bias layers, the first and second physically hard electrically insulating layers being constructed of a material that is resistant to removal by chemical mechanical polishing, and being formed such that no portion of the first and second physically hard electrically insulating layers extend over the sensor; and 
 
 a second electrode formed over said sensor and said physically hard electrically insulating layers.